Add query example

1 files changed, 183 insertions, 0 deletions

diff --git a/query/driver.cxx b/query/driver.cxx
new file mode 100644
index 0000000..15f6129
--- /dev/null
+++ b/query/driver.cxx
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+// file      : query/driver.cxx
+// author    : Boris Kolpackov <boris@codesynthesis.com>
+// copyright : not copyrighted - public domain
+
+#include <vector>
+#include <memory>   // std::auto_ptr
+#include <iostream>
+
+#include <odb/database.hxx>
+#include <odb/transaction.hxx>
+
+#include "database.hxx" // create_database
+
+#include "person.hxx"
+#include "person-odb.hxx"
+
+using namespace std;
+
+using odb::database;
+using odb::transaction;
+
+typedef odb::query<person> query;
+typedef odb::result<person> result;
+
+static void
+print (result& r)
+{
+  for (result::iterator i (r.begin ()); i != r.end (); ++i)
+  {
+    cout << i->first () << " " << i->last () << " " << i->age () << endl;
+  }
+
+  cout << endl;
+}
+
+int
+main (int argc, char* argv[])
+{
+  try
+  {
+    auto_ptr<database> db (create_database (argc, argv));
+
+    {
+      typedef vector<person> people;
+
+      people p;
+
+      p.push_back (person ("John", "Doe", 21));
+      p.push_back (person ("John", "Smith", 22));
+      p.push_back (person ("Jack", "Johnson", 31));
+      p.push_back (person ("John", "Jackson", 32));
+      p.push_back (person ("Jane", "Doe", 23));
+      p.push_back (person ("Jane", "Smith", 24));
+
+      transaction t (db->begin_transaction ());
+
+      for (people::iterator i (p.begin ()); i != p.end (); ++i)
+        db->persist (*i);
+
+      t.commit ();
+    }
+
+    // A simple query and result handling.
+    //
+    {
+      transaction t (db->begin_transaction ());
+
+      result r (db->query<person> (query::age < 30));
+
+      for (result::iterator i (r.begin ()); i != r.end (); ++i)
+      {
+        cout << i->first () << " " << i->last () << " " << i->age () << endl;
+      }
+
+      // Alternatively we can get a dynamically-allocated object.
+      //
+      /*
+      for (result::iterator i (r.begin ()); i != r.end (); ++i)
+      {
+        auto_ptr<person> p (i.load ());
+        cout << p->first () << " " << p->last () << " " << p->age () << endl;
+      }
+      */
+
+      // Or we can load the state into an existing object.
+      //
+      /*
+      person p ("", "", 0);
+
+      for (result::iterator i (r.begin ()); i != r.end (); ++i)
+      {
+        i.load (p);
+        cout << p.first () << " " << p.last () << " " << p.age () << endl;
+      }
+      */
+
+      cout << endl;
+
+      t.commit ();
+    }
+
+    // Query that shows how to combine expressions with &&, ||, and !
+    // as well as use paranthesis to control evaluation order.
+    //
+    {
+      transaction t (db->begin_transaction ());
+
+      result r (
+        db->query<person> (
+          (query::first == "John" || query::first == "Jane") &&
+          !(query::last != "Doe" || query::age > 30)));
+
+      print (r);
+      t.commit ();
+    }
+
+    // Query that shows how to use by-reference parameter binding.
+    //
+    {
+      transaction t (db->begin_transaction ());
+
+      unsigned short lower, upper;
+
+      query q (query::age >= query::_ref (lower) &&
+               query::age < query::_ref (upper));
+
+      for (unsigned short band (0); band < 10; ++band)
+      {
+        lower = band * 10;
+        upper = lower + 10;
+
+        result r (db->query<person> (q));
+
+        if (!r.empty ())
+        {
+          cout << lower << '-' << (upper - 1) << ':' << endl;
+          print (r);
+        }
+      }
+
+      t.commit ();
+    }
+
+    // Query that shows how to use the in() function.
+    //
+    {
+      transaction t (db->begin_transaction ());
+
+      result r (
+        db->query<person> (
+          query::last.in ("Smith", "Johnson", "Jockson")));
+
+      print (r);
+
+      t.commit ();
+    }
+
+    // The same query but using the in_range() function.
+    //
+    {
+      vector<string> names;
+
+      names.push_back ("Smith");
+      names.push_back ("Johnson");
+      names.push_back ("Jockson");
+
+      transaction t (db->begin_transaction ());
+
+      result r (
+        db->query<person> (
+          query::last.in_range (names.begin (), names.end ())));
+
+      print (r);
+
+      t.commit ();
+    }
+  }
+  catch (const odb::exception& e)
+  {
+    cerr << e.what () << endl;
+    return 1;
+  }
+}